Operate in API mode
API mode overview
XBee 868LP RF Modules User Guide
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API mode overview
As an alternative to Transparent operating mode, you can use API operating mode. API mode provides
a structured interface where data is communicated through the serial interface in organized packets
and in a determined order. This enables you to establish complex communication between devices
without having to define your own protocol. The API specifies how commands, command responses
and device status messages are sent and received from the device using the serial interface or the
SPI interface.
We may add new frame types to future versions of firmware, so build the ability to filter out additional
API frames with unknown frame types into your software interface.
API frame format
The firmware supports two API operating modes: without escaped characters and with escaped
characters. Use the AP command to enable either mode. To configure a device to one of these modes,
set the following AP parameter values:
n
AP
= 1: API operation.
n
AP
= 2: API operation (with escaped characters—only possible on UART).
The API data frame structure differs depending on what mode you choose.
API operation (AP parameter = 1)
The following table shows the data frame structure when you enable
AP
= 1:
Frame fields
Byte
Description
Start delimiter
1
0x7E
Length
2 - 3
Most Significant Byte, Least Significant Byte
Frame data
4 - n
API-specific structure
Checksum
n + 1
1 byte
The firmware silently discards any data it receives prior to the start delimiter. If the device does not
receive the frame correctly or if the checksum fails, the device replies with a device status frame
indicating the nature of the failure.
API operation-with escaped characters (AP parameter = 2)
This mode is only available on the UART, not on the SPI serial port. The following table shows the data
frame structure when you enable
AP
= 2:
Frame fields
Byte Description
Start delimiter 1
0x7E
Length
2 - 3
Most Significant Byte, Least Significant Byte
Characters escaped if needed
Frame data
4 - n
API-specific structure
Checksum
n + 1 1 byte
